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PostPosted: Mon May 12, 2008 10:16 am
I suggest you buy a bottle of the Stewart System water based cement and give it try on something other than your Lazair. You could make up some test panels using form and aluminum. You can also cover a control surface or two to see if you like using the system. You can also check out their web site to get some idea of how the system works.

We capped our ribs with 3 inch Dacron finish tape wrapped over the aluminum cap strips and cemented to both the cap strips and the Styrofoam ribs. We then wrapped the entire rib with a finish tape top to bottom in a X fashion like the original packing tape and light lightly ironed the tape to make it tight (using 250 degrees and a thin piece of aluminum to protect the rib from the iron). The result is a very sturdy rib with a good top and bottom surface to cement the wind covering to.

Next we applied cement to the leading edge on the “D” tub, the tops surface of the rib and the trailing edge. We let the cement dry (about a hour) then rolled out the top wing cover material ( 1.7 oz Dacron 72 inches wide ). Using a model airplane iron we tacked the material in place pulling it as smooth as possible. Then we applied the cement as per the system instructions to the leading and trailing edge and to the rib caps and all other places that required cement. We let that cement dry completely then ironed the entire wing cover at 250 degrees which removed all the wrinkles and tightened the wing cover. We then repeated this process for the bottom wing cover. The cover is attached to the ribs initially by ironing the cover to the dried cement underneath. The cement is applied through the wing cover which bonds the wing cover to the rib. No rib stitching is needed and you don’t have to apply weights to the bottom wing cover when cementing it. After the wing is covered entirely we ironed it again at about 300 degrees taking care not to pull the fabric too tight. There is only a slight scalloping of the trailing edge.

After the covering was completed we applied 3 coats of white exterior latex house paint primer then two coats of white latex exterior enamel. This was very easy to do and hopefully will provide plenty of UV protection. The results were better that we had hopped but only time will tell if this is a good way to cover a Lazair.

The Stewart System is STC’d for use on licensed aircraft but that is if you use their entire system including their primers and finish paints. That would be much more expensive then what we did but it has been tested over several years and found to be acceptable.


PostPosted: Tue May 13, 2008 11:33 pm
by Chappy
Thanks guys for the specifics on your covering jobs! Very informative and fill in many of the blanks I had about using the different covering systems.

I must admit that I am intrigued with the Hipec system, and a little prejudiced against the newer water based adhesive products (in general) that I have used over the years that have come along to replace the nasty old solvent based products that I have come to be confident (and competent) with. Maybe it's an old guy thing. Although, I must admit, the Stewart System adhesive looks like interesting stuff too!

The main reason I think I would like to try the Hipec system is that it just seems to address all the things I don't really like about the Poly-Fiber system (that I'm familiar with) w/o starting from scratch from my experience base - if that makes any sense to you.


PostPosted: Wed May 14, 2008 10:01 am
by bdiedenhofen
Yeah, most systems require a fill coat, then silver, then colour, and they all require mechanical fastening. That's where Hypec really shines. Fill, adhesive, and silver are all in the same two initial coats. Then it's just colour. I really like the stuff. They've got some really nice top paints as well, but expensive. Latex works very well, and is really easy to repair.
I was thinking pretty seriously about Stewarts for my next project, but the simplicity of the Hypec will probably keep me with that process for the basic covering.
I hate solvents though, so I'm definately using Stewarts primer for the framework, and paint for the metal parts. I'll likely use the Stewarts fabric adhesive for the initial tacking of the cloth.

PostPosted: Thu May 15, 2008 1:22 pm
by JPXman
i'm curious:

why do some lazairheads cover their tail feathers/ailerons in fabric and the rest in tedlar?

Re: Our Recovered Lazair III

PostPosted: Sun Jan 04, 2015 1:09 pm
by 320drvr
Hi Jerry,

I'm considering your method to cover and paint my Lazair . Can you add any comments or observations 7 yrs down the road ?